The info provided with the cam should tell you the recomended breakin... Contact you cam manufacture if you can't find their instructions. Cams tend to go bad in the first 50 - 100 miles. Do it right, you won't regret it! I have never seen anyone warm up the motor before breakin. Breakin is a turn the key and get the revs up now deal! The only reason to stop during this time is if you have a gas leak or no oil pressure.
Be safe and smart, don't try to fire it up with the floor jack holding the motor up! Finish your install first. You will have plenty of time to fire it when done and you will be on the road sooner after firing it up that way. As for the noise give your neighbors some warning and let them know it's heading to the muffler shop asap after breaking in the cam. I hope you ment open headers when you said "open heads". Good luck and have fun!
